The invention relates to an oxidation/coagulation system for the purification of water, primarily for use with aquariums. A generally similar system for aqueous electroytes is disclosed in co-pending application Ser. No. 841,925 filed Oct. 13, 1977, now U.S. Pat. No. 4,161,435, the disclosure of which is hereby incorporated by reference herein.
In treating water to be inhabited by aquatic life, especially for limited volume systems such as aquariums, it is necessary and/or desired to eliminate organic and inorganic metabolites, eliminate particulate matter in suspension, eliminate colloidal matter, eliminate yellowing or organic dyes, and destroy pathogens (bacteria, viruses, fungus, parasites and their spores). At present, in order to accomplish all of the above results even moderately effectively, it is necessary to provide a large amount of diverse equipment. For instance, organic and inorganic metabolites and decay products are removed by biological gravel filters, ozonation, foam fractionation, or activated carbon. However, activated carbon tends to remove vitral trace elements, and other systems have other disadvantages associated therewith. Particulate matter is removed by mechanical filters, and colloidal matter is only partially removed by mechanical filters. Organic dyes are removed by activated carbon which--as mentioned above--has the disadvantage of removing vital trace elements, and pathogens are destroyed by ozonation in ultraviolet light.
According to the present invention, it is possible to accomplish all the desirable results mentioned bove (i.e., elimination of metabolites, elimination of particulate matter in suspension, etc.) in a simple and effective manner, utilizing simple, relatively inexpensive equipment.
According to the apparatus of the present invention, a water purification assembly is provided comprising means for withdrawing water from a water source (aquarium); means for effecting oxidation and coagulation of metabolites in the water, the means comprising a chamber into which the withdrawing means feeds water, a plurality of electrodes disposed in the chamber and connected up to a source of e.m.f., a plurality of electrically conductive particles each with a relatively large surface area configuration disposed in the chamber, means for violently continuously circulating the particles within the chamber so that they can continuously impact all of the electrodes, and means for preventing movement of the electrically conductive particles out of the chamber; an outlet from the chamber; and means connected to the chamber outlet for mechanically separating particles and coagulants from the water and then returning the now-purified water to the water source. The violent, continuous circulation may be provided by a nozzle formed in a conduit from a pump which provides the withdrawing means. The stream of water under pressure from the pump being directed downwardly in the chamber and circulating the particles downwardly, around a curved surface, upwardly, and then flowing back downwardly to be entrained in the flow again. The curved surface may be perforated and the outlet disposed on the opposite side thereof.
The electrodes are preferably disposed horizontally and can be made of stainless steel, graphite, platinum-coated titanium or the like. The mechanical separating means may comprise a diatomaceous earth filter or the like, and conduit means are provided between the chamber and the mechanical separation means to insure that air bubbles entrained in the water from the chamber are released to the atmosphere before being fed to the filter. All of the components can be mounted directly adjacent and/or on a conventional aquarium. If desired, a pre-filter may be provided between the withdrawing means and the chamber for removing large particulates.
According to the preferred method of the present invention, the purification of salt water is effected by oxidation and coagulation of metabolites in the water utilizing the chamber having a plurality of stainless steel horizontally disposed electrodes therein which are connected up to an e.m.f. source, the purification being effected without rusting of the electrodes even over extended operation and practice of the method. The method comprises the steps of disposing a plurality of conductive particles in the chamber, each particle having a relatively large surface area configuration and being denser than salt water; feeding water into the chamber; continuously and violently circulating the particles in the chamber in a flow path so that they continuously impact all of the electrodes; withdrawing water from the chamber after passage thereof between at least some of the electrodes and particles while preventing removal of the particles; and mechanically separating particles and coagulants from the water withdrawn from the chamber. The voltage applied by the e.m.f. source, which preferably is AC, is such that a maximum density of about 0.5 amp./in..sup.2 is provided. The circulation path of the particles is normally generally downwardly, curving back upwardly, moving generally upwardly, and then eventually again moving downwardly in a random manner. The method may be as described above, and consisting essentially of the further step of pre-filtering water before feeding into the chamber, to remove large particles therefrom.
It is the primary object of the present invention to provide an improved method and apparatus for the oxidation and/or coagulation of water, especially for aquarium use. This and other objects of the invention will be clear from an inspection of the detailed description of the invention, and from the appended claims.